Overall water splitting by sonophotocatalytic reaction: the role of powdered photocatalyst and an attempt to decompose water using a visible-light sensitive photocatalyst

The role of a photocatalyst in the sonophotocatalytic reaction of water was investigated using TiO2 photocatalysts. Based on this investigation, sonophotocatalytic water splitting using visible light was attempted. BiVO4 is a visible light-sensitive material and this material is one of the candidates for O-2 evolution photocatalyst. For example, O-2 is evolved from H2O2 solution by photocatalytic reaction under visible light irradiation. On the other hand, Hz is produced together with H2O2 from water by irradiation of ultrasound. Thus, it is expected to obtain H-2 and O-2 from water when these two reaction systems are combined. Simultaneous irradiation of visible light and ultrasound was tried to perform. As the result, liquid water was decomposed to H-2 and O-2 continuously and stoichiometrically. (C) 2001 Elsevier Science B.V. All rights reserved.